N-axkenxl-aminophenol



, Patente'd'June 1c, 1942 N-AIKENYL-AMINOPHENOL Ivan Gubelmann, Wilmington, DeL, asslgnor to E. L du Pont cle Nemours & Oompany, Wilmington, 'Del., a corporation of Delaware No Drawing. Application March 21, 1940, Serial No. 325,111

a 16 Claims. (01. 260 -574) This invention relates to new N-alkenyl aminophenols.

It is an object of the present invention to provide new and useful N-substituted aminophenols.

Another object is to provide new N-substituted aminophenols in which at least one ofthe substituents on the, nitrogen is an unsaturated aliphatic radical. A further object is to provide a method of preparing such new chemical compounds. Further objects are to advance the art. Still other objects will appear hereinafter.

The above and other objects may be accomplished in accordance with my invention, which comprises the preparation of N-substituted aminophenols of the benzene series, in which the nitrogen is in one of the positions ortho and para to the hydroxyl group and in which, at least one of the substituents on the nitrogen, is an alkenyl or chloroalkenyl group, and which aminophenols are new chemical compounds, not known heretofore. The compounds of my invention maybe employed to improve the stability of gasoline, fats, oils, waxes and rubber, and particularly to inhibit oxidation and gum formation. They are particularly useful for such purpose in motor fuels, especially those containing cracked gasoline and which may or may not contain antiknock agents, such as tetraethyl lead. They may be employed in conjunction with other additives, such as pour-point improvers, viscosity-index improvers, corrosion inhibitors, polymerization inhibitors and the like, when employed in petroleum. oils, such as lubricating oils, transformer oils, over-head lubricants, extreme pressure lubricants and the like. They may be employed as photographic developers and as intermediates in the preparation of dyes, pharmaceuticals, cosmetics and the like. The presence of one or more active double bonds in the alkenyl chain makes the compounds more useful in a number of cases, such as intermediates, than their saturated analogues. By the term bl-substituted, I mean' that the nitrogen of the amino group contains substituents, that is, that one or more hydrogens of ,the

double bonds in the chain. By the termchloroalkenyl," I mean alkenyl groups in which one or more of the hydrogens have been replaced by chlorine atoms. By the term bl-substituents," I mean a group or radical which has been substituted for a hydrogen of the amino group. By the term unsubstituted as applied to any of the compounds of my invention, I mean that the nitrogen contains only the substituents specifically named, and that the benzene ring contains no substituents except the amino and hydroxyl groups.

The compounds of my invention may be broadly designated as aminophenols containing a single benzene ring which may contain aliphatic hydrocarbon groups as substituents, but which otherwise contain no substituents other than the single hydroxy and amino groups, the hydroxy and amino groups being in one of the positions amino group have been substituted by an organic group. By the term "aminophenol of the benzene series, I mean a single benzene ring having one amino nitrogen and one hydroxyl group attached tocarbon atoms of the benzene ring, and which benzene ring contains no other substituents except aliphatic hydrocarbon radicals. By the term alkenyl, I mean an unsaturated aliphatic hydrocarbon group containing 1 or more ortho and para to each other and the nitrogen carrying one or more alkenyl or chloroalkenyl' groups. When the nitrogen contains only one alkenyl or chloroalkenyl group, it may also carry another hydrocarbon group such as an alkyl, aralkyl or aryl group. The most desirable compounds will be those in which the hydroxyl and amino groups are para to each other, that is, the p-aminophenols, and particularly those in which the benzene ring contains no substituents other than the hydroxyl and amino groups. Also the compounds with the most desirable properties are those in which the substituents on the nitrogen of the aminophenol are alkenyl or chloroalkenyl groups only.

While the compounds of my invention may be prepared by a number of different methods, they are preferably prepared by reacting an aminophenol with an alkenyl halide in the presence of a base as an acid acceptor. The reaction may be carried out in the absence of a solvent, but is preferably carried out in the presence of a solvent, such as an alcohol, an ether, a hydrocarbon, water or mixtures of two or more of such solvents. The preferred solvent is an alcohol, and particularly a low molecular weight alcohol, such as ethanol, methanol and propanol. The base, employed as an acid acceptor, may be an excess of the aminophenol itself or another organic base, such as pyridine or other tertiary amine, but is preferably an inorganic base, such as potassium carbonate, sodium carbonate, barium carbonate, sodium hydroxide, potassium hycarbonates of calcium, magnesium or zinc. I

particularly prefer to employ an alkali metal carbonate as the base or acid acceptor.

In order to illustrate my invention more clearly and particularly suitable methods of preparing representative compounds of my invention, the

following examples are given:

' EXAMPLE 1 N-allyl-p-aminophenol A mixture, of 55 parts of p-aminophenol (0.5

mole), 60 parts allyl bromide (0.5 m'ole) and 35 parts potassium carbonate (0.25 mole) in 300 parts by volume of 95% alcohol, was boiled under reflux with stirring for 24 hours. The hot mixture was then filtered from 42 parts of inorganic I parts of yellow oil, 13. P. 125-141 C./3 mm. To a solution of 23 parts of the distillate in 50 parts by volume of 95% alcohol was added 9 parts (1 equivalent) of oxalic acid dihydrate dissolved in part by volume of warm 95% alcohol. After cooling, the mixture was filtered from 11 parts of a crystalline oxalate. Crystallization of the oxalate from 400.parts by volume of 95% alcohol yielded 8 parts of purified N-allyl-p-aminophenol neutral oxalate as white needles, M. P. 198-200 0., containing 7.08% N (the theory for C20H2406N2 is 7.22% N). An aqueous suspension of 7 parts of the purified oxalate was treated with excess ammonium hydroxide and extracted with 60 parts by volume of ether. Distillation of the ether left an oil that crystallized when layered with 30-60" C. petroleum ether. The crystals were filtered off and were crystallized from 40 parts by volume of a 1:1 mixture of benzene and 30-60 C. petroleum ether. The product was 4 parts of N-allyl-p-aminophenol as hort white needles, M. P. 71 0., containing 9.15% N (the theory for C9H11ON is 9.39% N).

V EXAMPLE 2 N-diallyl-p-aminophenol theory for C1zH1sON is 7.40% N). The oil could not be obtained crystalline and did not give a crystalline sulfate, hydrochloride, oxalate, tartrate or benzoate from alcohol.

EXAMPLE 3 N- (Z-methyZ-Z-mopenyll) -p-aminophenol -A mixture of 109 parts p-aminophenol (1 mole), 136 parts methallyl chloride (1.5 mole) and 105 parts potassium carbonate (0.75 mole) in 1000 parts by volume of 95% alcohol was boiled under reflux with stirring for 24 hours. The

mixture was then cooled and was filtered from 93 parts of inorganic material. After removing the solvent from the filtrate by distillation under 200 H1111. pressure, the residue was slurried with 400 parts by volume of benzene and was filtered from 18 parts (16.5% of the starting material) of p-aminophenol. The filtratewas freed of solvent, and the residue was distilled under reduced pressure. The distillate was 119 parts of a yellow oil,'B. P. 140-160 C./0.5 mm., containing some solid. The distillate was taken up in parts by volume of cold 95% alcohol and was filtered from 5 parts (4.6% of the starting material) of p-aminophenol. On addition to the filtrate of a solution of 40 parts (1 equivalent) of oxalic acid dihydrate in 400 parts by volume of warm 95% alcohol, a precipitate promptly formed. After cooling, the mixture was filtered from 77 parts of an oxalate salt. This was purified by one crystallization from 1300 parts by volume of 95% alcohol and by two crystallizations from 1000 parts by volume of water. The purified salt was 44 parts of N-(2-methyi-2- propenyl) -p-aminopheno1 neutral oxalate as white needles, M. P. 191-192 C. (gas evolution), containing 6.81% N (the theory for C22H2aOeN2 is 6.73% N). An aqueous suspension of 15 parts of the purified salt was treated with excess ammonium hydroxide and extracted with 200 parts by volume of benzene. After drying over sodium sulfate, the benzene extract was diluted with 400 parts by -volume of 30-60" C. petroleum ether, cooled and filtered. The precipitate was 6 parts of N-(2-methyl-2-propenyl)-p-aminophenol as white needles, M; P. 71-73 0., containing 8.56% N (the theory forCmHnON is 8.58% N).

EXAMPLE 4 N-di-(Z-methyZ-Z-propenyl) -p-aminophenol The filtrate from the precipitation of N-(2- methyl-2-propenyl-p-aminophenol neutral oxalate, described in Example 3 above, was freed of solvent by distillation. An aqueous suspension of the residue was treated with excess ammonium hydroxide and extracted with benzene. The extract was dried, freed of solvent and distilled under reduced pressure. The distillate was 31 parts of a yellow oil, B. P. 120-140 C./0.5 mm. This was taken up in 300 parts by volume of 350-60 C. petroleum ether and filtered from a little p-aminophenol. The filtrate was freed of solvent, and the residue was distilled under reduced pressure. The distillate was 28 parts of a yellow oil, B. P. 120-125 C./0.5 mm, which partially crystallized on standing several days. This was purified by three crystailizations from 30-60 C. petroleum ether. The purified base was 5 parts of N-di-(2-methyl-2-propenyl)-paminophenol as white crystals, M. P. 50-51 0.. containing 6.53% N (the theory for C14Hi9ON is 6.45% N). The base 'gives a crystalline hydro- .chloride'and sulfate from alcohol.

EXAMPLE 5 N-di-(3-chloro-2-butenyl) -p-aminophenol A mixture of 109 parts p-aminophenol (1 mole), 188 parts 1,3-dichloro-2-butene (1.5 moles) and .parts potassium carbonate in 1000 parts by volume of 95% alcohol was boiled under reflux with stirring for 24 hours. After cooling, the mixture was filtered from 99 parts inorganic material, and the filtrate was freed of solvent by distillation on a steam bath under 200 mm. pressure. The residue was taken up in 1500 parts by volume of benzene and filtered from some tarry solid. Removal of solvent from the filtrate on a steam bath under 200 mm. pressure left 172 parts of a red oil. To this oil, dissolved in 100 parts by volume of 95% alcohol, was added a solution of 42 parts oxalic acid dihydrate in 200 parts by volume of 95% alcohol. After standing 2 days at room temperature, the mixture was filtered from 138 parts of oxalate salt. This salt was purified by two crystallizations from 600 parts by volume of 95% alcohol and one crystallization from 700 parts by volume of 95% alcohol. The purified salt was 69 parts of N-di-(3-chloro-2- butenyl) -p-aminophenol neutral oxalate as white crystals, M. P. 117-118 C., containing 4.24% N, 21.22% Cl, 5.29% H and 54.61% C (the theory for CaoHaeOcNzCh is 4.23% N, 21.42% Cl, 5.48% H and 54.36% C). An aqueous suspension of 15 parts of the purified salt was treated with excess ammonium hydroxide and extracted with 100 parts by volume of benzene. The extract was dried and was freed of solvent to 100 C. at 0.5

- mm. pressure. The residue was 10 parts of N-di- (3-chloro-2-butenyl) -p-aminophenol as a yellow oil that did not crystallize and contained 24.34%

Cl and 4.86% N (the theory for C14H1-10NCl: is 24.80% C1 and 4.88% N).

EXAMPLE 6 N-(3-chloro-2-butenyl) -p-aminophenol The filtrates from the preparation and purification of N -di-(3-chloro2- butenyl) -p-aminophenol neutral oxalate, described in Example above, were combined and were freed of solvent by distillation. An aqueous suspension of the residue was treated with excess ammonium hydroxide and extracted with 200 partsby volume of benzene. The extract was diluted with 1800 parts by volume of benzene. This dilution precipitated a tarry material that was filtered oil? and discarded. Removal of solvent from the filtrate left 81 parts of a red oil. To this oil, dissolved in 100 .parts by volume of 95% alcohol,

was added a solution of 26 parts oxalic acid dihydrate in 200 parts by volume of 95% alcohol. After standing over-night, the mixture was illtered from 13 parts of oxalate salt. This was purified by one crystallization from 250 parts by volume of 95% alcohol. The purified salt was 10 parts of N-(3-chloro-2-butenyl)-p-aminophenol acid oxalate as white crystals, M. P. 196-199 C. (gas evolution), containing 12.42% Cl and 4.82% N (the theory for C12H14O5NC1 is 12.33% Cl and 4.87% N). An aqueous suspension of the purified salt was treated with excess ammonium hydroxide and extracted with 100 parts by volume of benzene. The extract was dried, diluted with 250 parts by volume of 30-60 C. petroleum ether and filtered. The precipitate was 3.4 parts of N-(3-chloro-2-butenyl) -p-aminophenol as yellow crystals, M. P. Gil-61 0., containing 17.93% Cl and 7.08% N (the theory for CroHrzONCl is 17.95% Cl and 7.09% N).

The above examples are given-for illustrative purposes only. It will be readily apparent to those skilled in the art that many variations and modifications may be made therein, particularly in the starting materials, the process of making the compounds and the compounds produced, without departing from the spirit of my invention. For example, other compounds within my invention are:

N-allyl-o-aminophenol V N-diallyl-o-aminophenol N-methyl-N-allyl-p-aminophenol N-.benzyl-N-allylp-aminophenol N-vinyl-p-aminophenol N-vinyl-o-aminophenol N- (2-ethy1-2-hexenyD -p-aminophenol N- (3-propenyl) -p-aminophenol N- (4-hexenyl) -p-aminophenol N- (hexa-2,4-dienyl) -p-aminophenol N (penta-1,3-dienyl) -p-aminophenol N-allyl-4-amino-2-isopropyl phenol N-allyl-4-amino- 2,5-diisopropyl phenol N-divinyl-p-aminophenol N-di(2-ethyl-2-hexenyl) -p-aminophenol N-di(3-prqpenyl) -p-aminophenol N-di(4-hexenyl) -p-aminophenol N-di(hexa-2,4-dienyl) -paminophenol N-diallyl-4-amino-2-isopropyl phenol N-diallyl-i-amino-2,5-diisopropyl phenol The compounds of my invention may be prepared by other methods, such as bycondensing a dihydroxy benzene, for example, hydroquinone or catechol, with an alkenyl or dialkenyl amine, for example, allyl amine or diallyl amine. They may be prepared by condensation of an aminophenol with an unsaturated aldehyde, such as cotonaldehyde or alpha-ethyl-beta-propyl acrolein, followed by selective hydrogenation of the resulting alkenylidene aminophenol under conditions that add hydrogen to the N --C'linkage leaving the C-'-C linkage of the alkenylidene group unreduced or under conditions that add hydrogen to the 1 and 4 positions of the system leaving a compound containing the system Also they may be prepared by dehydrohalogenation or dehydration of an N-alkyl aminophenol having a halogen or a hydroxyl group attached to the alkyl group. Other methods of preparing the compounds of my invention will be apparent to those skilled in the art.

I claim:

1. An N-substituted aminophenol of the henzene series in which the nitrogen is in one of the positions ortho and para to the hydroxyl group and in which one substituent on the nitrogen is a member of the group consisting of alkenyl and chloroalkenyl groups and the other substituent is a member of the group'consisting of hydrogen, hydrocarbon and chloroalkenyl groups.

2. An N-alkenyl aminophenol of the benzene series in which the nitrogen is in one of the posi- 4. An N-alkenyl p-aminophenol of the benzene series.

5. An N-monosubstituted p-aminophenol of the "benzene series in which the N-substituent is a member of the group consisting of alkenyl and chloroalkeny groups.

6. An N-monoalkenyl p-aminophenol of the benzene series.

7. An unsubstituted N-monoalkenyl p-aminophenol.

8. An N-allyl aminophenol of the benzene series 13. An unsubstituted N-dialkenyl p-amlnoin'whlch the nitrogen is in one otthe positions I phenol.

ortho and para to the hydroxyl group; 14. An N-diallyl p-aminophenol of the benzene 9. An N-allyl p-aminophenol or the benzene series.

series. 5 15. N-dlallyl p-amlnophenol.

10. An unsubstituted N-allylp-aminophenol. 16. N-(2-methyl-2-propeny1) -p'-aminopheno1. .111. N-allyl p-aminophenol.

12. An N-dialkenyl p-aminophenol or the benv IVAN GUBEIMANN.

zene series.

CERTIFICATE OF CORRECTION. Patent No. g, 86,678. I June 16,19142.

IVAN emafimmlm.

It is hereby eertifi'ed that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 3, sec- 6nd column, 1ine 6, for "cotonaldehyde'f read. --crotona1dehyde--; and that the said Letter-e Patent shou1d be read-with this correctibn therein that the same may'confem to the record of the case in the Patent Office.

Signed and sealed this 25th day "or August, A. D. 191;.2.

Henry Van Arsdale,

(Seal) Acting Commissioner 5r Patents. 

